[PATCH AUTOSEL 6.12 10/26] ASoC: intel/sdw_utils: Assign initial value in asoc_sdw_rt_amp_spk_rtd_init()

[Sasha Levin <sashal@kernel.org>]

From: I Hsin Cheng <richard120310@gmail.com>

[ Upstream commit 5fb3878216aece471af030b33a9fbef3babd8617 ]

Initialize "ret" with "-EINVAL" to handle cases where "strstr()" for
"codec_dai->component->name_prefix" doesn't find "-1" nor "-2". In that
case "name_prefix" is invalid because for current implementation it's
expected to have either "-1" or "-2" in it. (Maybe "-3", "-4" and so on
in the future.)

Link: https://scan5.scan.coverity.com/#/project-view/36179/10063?selectedIssue=1627120
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
Link: https://patch.msgid.link/20250505185423.680608-1-richard120310@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

Based on my analysis of the commit and the codebase context, I can now
provide a comprehensive assessment: **YES** This commit should be
backported to stable kernel trees. ## Extensive Analysis ### Nature of
the Bug The commit addresses a classic uninitialized variable bug in
`asoc_sdw_rt_amp_spk_rtd_init()` in
`sound/soc/sdw_utils/soc_sdw_rt_amp.c`. The function declares `int ret;`
but only conditionally assigns values to it within a loop: ```c
for_each_rtd_codec_dais(rtd, i, codec_dai) { if
(strstr(codec_dai->component->name_prefix, "-1")) ret =
snd_soc_dapm_add_routes(&card->dapm, rt_amp_map, 2); else if
(strstr(codec_dai->component->name_prefix, "-2")) ret =
snd_soc_dapm_add_routes(&card->dapm, rt_amp_map + 2, 2); } return ret;
``` ### When the Bug Manifests The bug occurs when: 1.
`codec_dai->component->name_prefix` doesn't contain "-1" OR "-2" 2. Both
`strstr()` calls return NULL, causing neither branch to execute 3. The
function returns an uninitialized `ret` value, leading to unpredictable
behavior ### Historical Context From the git blame analysis, this bug
was introduced in commit `84e0a19adb73d` (May 9, 2024) by Bard Liao when
adding a dai parameter to rtd_init callbacks. The commit changed the
variable name from `dai` to `codec_dai` to avoid conflicts, but failed
to initialize `ret` properly for the edge case. ### Code Analysis The
fix is simple and correct: - **Before**: `int ret;` (uninitialized) -
**After**: `int ret = -EINVAL;` (initialized with appropriate error
code) The `-EINVAL` choice is appropriate because: 1. If name_prefix
lacks "-1" or "-2", it indicates an invalid configuration for current
implementation 2. The commit message explicitly states this expectation
3. `-EINVAL` is the standard Linux kernel error for invalid arguments
### Static Analysis Context The commit message references Coverity scan
ID 1627120, indicating this was caught by static analysis tools. This is
a legitimate bug that could cause: - Random return values leading to
unpredictable behavior - Potential system instability in audio subsystem
- Difficult-to-debug intermittent failures ### Backport Suitability
Analysis **✅ Meets Stable Tree Criteria:** 1. **Important Bug Fix**:
Fixes a real bug that can cause unpredictable behavior in the audio
subsystem 2. **Small and Contained**: Single line change, minimal risk
of introducing regressions 3. **No Side Effects**: Only affects the
error path when name_prefix is invalid 4. **No Architectural Changes**:
Pure bug fix with no design changes 5. **Subsystem Confined**: Limited
to ASoC Intel SDW utils subsystem 6. **Clear Benefit**: Prevents
undefined behavior and ensures deterministic error handling **Risk
Assessment**: **VERY LOW** - Single line initialization change - Only
affects error/edge case paths - No functional logic changes - Well-
understood fix pattern **Impact**: **MODERATE** - Affects Intel
SoundWire audio configurations - Could prevent audio system failures on
affected hardware - Improves system reliability and debuggability ###
Comparison with Similar Commits The provided examples show that simple
NULL check additions (Similar Commit #1) and small contained bug fixes
are consistently marked as "YES" for backporting. This commit follows
the same pattern - it's a small, contained fix for a legitimate bug with
minimal risk. This commit exemplifies the ideal stable tree candidate:
it fixes a real bug, is minimal in scope, has no risk of regression, and
improves system reliability.

 sound/soc/sdw_utils/soc_sdw_rt_amp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/sdw_utils/soc_sdw_rt_amp.c b/sound/soc/sdw_utils/soc_sdw_rt_amp.c
index 6951dfb565263..b3d6ca2499734 100644
--- a/sound/soc/sdw_utils/soc_sdw_rt_amp.c
+++ b/sound/soc/sdw_utils/soc_sdw_rt_amp.c
@@ -190,7 +190,7 @@ int asoc_sdw_rt_amp_spk_rtd_init(struct snd_soc_pcm_runtime *rtd, struct snd_soc
 	const struct snd_soc_dapm_route *rt_amp_map;
 	char codec_name[CODEC_NAME_SIZE];
 	struct snd_soc_dai *codec_dai;
-	int ret;
+	int ret = -EINVAL;
 	int i;
 
 	rt_amp_map = get_codec_name_and_route(dai, codec_name);
-- 
2.39.5